Abstract

Grammatical intricacy is an important concept in charactering complexity of language (Halliday, 2008). However, this concept has not yet been fully investigated in the teaching and learning of English as a foreign language (TEFL), particular in English as a foreign language (EFL) textbooks in higher education. This paper aims to examine grammatical intricacy across textbook levels in a book series used in tertiary education in the Vietnamese context. This is part of a larger research project looking at linguistic complexity of English textbooks in the TEFL setting. The research employed Systemic Functional Linguistics (SFL) as the main theoretical framework and Halliday’s method as a measure of grammatical intricacy to look at how this language feature was used in reading comprehension texts in four textbooks at different levels including elementary, pre-intermediate, inter-mediate and upper-intermediate. The findings revealed that grammatical intricacy increased in accordance with the book levels. Particularly, the mean scores of grammatical intricacy showed a gradual increase from the elementary to the intermediate book level; though they were not different significantly and the upper-intermediate textbook did not show the topmost grammatical complexity. These findings suggest that the use of grammatical intricacy in the investigated textbooks was appropriate for EFL learners across levels; however, the use of other linguistic features such as lexical density and nominalisation may potentially impact the use of simple clauses in the textbooks at a higher level. Thus, further investigations are recommended to fully explore the complexity of textbook language.